FIG. 18 is a schematic configuration showing a state, in which an injector is mounted on a cylinder head of an engine.
In the case where an injector 50 is mounted on a cylinder head 60 of an engine, it is necessary to prevent leakage of a combustion gas from a neighborhood of a mount of the injector 50.
Thus, washer-shaped seals 100, 101 are conventionally provided in two locations on the mount of the injector 50 as shown in FIG. 18 to prevent leakage of a combustion gas.
The seals 100, 101 are formed from metal such as copper, or the like, and sealing is achieved by a clamping force Q (see FIG. 19), which is obtained by a fastening force when the injector 50 is mounted on the cylinder head 60 of an engine. In addition, for example, as shown in FIG. 18, the fastening force can be obtained by screwing an external thread portion provided on the injector 50 into an internal thread portion provided on the cylinder head 60.
With the above conventional art, however, sealing of the metallic washer-shaped seals 100, 101 is achieved by utilization of the clamping force, so that vibrations caused by an engine or the like are transmitted to the seals 100, 101 to produce a large sound at the sealed portion, which is responsible for noise.
Also, load based on vibrations and heat causes reduction in the clamping force whereby a sealing performance is degraded with the passage of time.
An object of the invention is to provide a combustion gas seal for injectors, which improves a sound insulation effect and a sealing performance.